Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The enzyme preparation of L(+)-lactatoxydase (K.F. 1.1.3.2) with molecular weight of 230 000 has been isolated from the soluble fraction of the C. lipolytica cells and purified similar 360 times. The enzyme oxydizes L(+)-lactate, the optimum activity of the enzyme being observed at pH 8.0. Oxydation of the substrate is followed by accumulation of H2O2. Silver ions, p-chloromercurybenzoate and dicumarol inhibit the activity of L(+)-lactatoxydase. Iron complexones, cyanide and L-malate do not inhibit oxydation of the substrate. Pyruvate and its fluorine derivative practically do not produce any inhibiting effects either. The enzyme preparation contains 0.6 moles of flavin and 2 moles of nonhaem iron per a mole of the enzyme. Km value for the substrate is equal to 4-10(-4) M, Vmax--4.5 mkatom O/min/mg. Acidation of incubation medium leads to a decrease both of Km and Vmax. Km value for oxygen is equal to 3.1 mkM O2. Beside oxygen, ferricyanide, 2.6-dichlorphenolindophenol, phenazine methosulphate and cytochrome C may also serve as acceptors of L(+)-lactatoxydase electrons. The oxydized enzyme preparation is characterized by a spectrum absorption maximum at 410 nm. Upon L(+)-lactatoxydase reduction the maximum is shifted up to 420 nm.
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PMID:[Isolation and properties of cytoplasmic L(+)-lactatoxydase of Candida lipolytica yeasts]. 1 33

Glutathione peroxidase (glutathione:H2O2 oxidoreductase, E.C. 1.11.1.9), isolated from ovine and bovine erythrocytes, has recently been shown to contain 4 selenium atoms per mole, an average of 1 Se per protein subunit of about 22,000 molecular weight. Selenium deficiency in the rat, chick and sheep causes dramatic decreases in the activity of this enzyme in the tissues, but certain sites such as liver are affected more than others. Decreases in glutathione peroxidase correlate with lesions caused by selenium deficiency and appear useful in diagnosing selenium deficiency. Glutathione peroxidase is an important enzyme in destroying H2O2 and organic hydroperoxides such as lipid hydroperoxides. It therefore guards against oxidative damage to the cell membranes and other oxidant-sensitive sites in the cell. While this selenium-dependent system destroys lipid hydroperoxides and other peroxides, vitamin E is believed to protect against oxidant damage to membranes by preventing the formation of lipid hydroperoxides. A scheme is proposed, based on oxidant damage and its prevention, which accounts for the interaction between selenium, vitamin E, unsaturated lipids, sulfur-containing amino acids, and cell damaging agents such as oxidant stressors and toxicants such as silver and tri-o-cresyl phosphate. The background for such a scheme is reviewed.
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PMID:Biochemical function of selenium and its relation to vitamin E. 110 Apr 37

The following methods are described for the analytical investigation of pipecuronium bromide. 1. HPLC method. Of the several systems tried for the separation and quantification of impurities and degradation products the best results were obtained using silica as the stationary phase and 43:43:14 mixture of methanol, acetonitrile and concentrated aqueous ammonia containing 0.1 mole/l each of ammonium chloride and ammonium carbonate as the eluent. The validation of this method is presented. The above described aggressive eluent can be successfully replaced by an ion-pairing system using silica as the stationary phase and 96:4 mixture of acetonitrile and water containing 0.1 mole/l sodium perchlorate as the eluent. 2. Thin-layer chromatography. TLC systems are described for the separation and densitometric quantification of the impurities and degradation products of pipecuronium bromide. 3. Spectrophotometry. Two methods are described. The ester groups of the molecule can be determined by the iron(III)-hydroxamate method while for the ion-pair extraction of the quaternary ammonium steroid picric acid or bromthymol blue are used as the reagents. 4. Titrimetry. In addition to the titration with acetous perchloric acid for the assay of the bulk material a microtitration method is described for the determination of pipecuronium bromide in individual lyophylized ampoules (potentiometric titration with 0.1 M silver nitrate).
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PMID:[Analysis of steroids. Part 45: Analytical investigation of pipecuronium bromide (Arduan)]. 132 18

The silver staining of nucleolar organizer region-associated proteins is an objective method that has been used to differentiate benign from malignant neoplasms. Recently this method was used to distinguish benign choroidal nevi from malignant choroidal melanomas. We studied 24 iris melanocytic lesions to assess the applicability of this technique for differentiating benign from neoplastic iris tumors. Masked observers determined the number of silver-stained nucleolar organizer region dots per cell for silver-stained specimens. Iris nevi contained a mean of 1.6 silver-stained nucleolar organizer region dots per cell, whereas iris (spindle A and B, spindle B, epithelioid, mixed cell) malignant melanomas contained a mean of at least 3.5 silver-stained nucleolar organizer region dots per cell (P less than .0001). All iris nevi demonstrated counts lower than 1.9, whereas all iris melanomas demonstrated counts greater than 2.8. Silver-stained nucleolar organizer region counts were also compared with the clinicopathologic variables of gender, age, and largest specimen dimension. Only the largest specimen dimension correlated with silver-stained nucleolar organizer region counts (P less than .0029). The silver-stained nucleolar organizer region method is a simple technique for differentiating iris nevi from iris melanomas. The silver-stained nucleolar organizer region technique may aid in the assessment and treatment of iris lesions by confirming the malignancy of biopsy specimens.
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PMID:Nucleolar organizer regions in iris nevi and melanomas. 164 96

We review two patients with unusual pilosebaceous and spindle cell neoplasms. Both lesions were on the nose and were clinically similar to angiofibroma. Immunoperoxidase (S-100 protein, vimentin, immunostain for actin) and special stains (Masson's trichrome, periodic acid-Schiff, and Bielschowsky silver stain) were used to evaluate the lesions. The histologic differential diagnosis included neural nevi, trichogenic myxoma, trichodiscoma, benign neural and vascular tumors, and dermal scar formation. Our patients, we believe, had single asymptomatic smooth, skin-colored papules; this condition was recently termed "neurofollicular hamartoma."
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PMID:Neurofollicular hamartoma. A clinicopathological study. 165 45

Silver staining of nucleolar organizer regions is an objective method for evaluating the malignancy of a variety of tumors. We studied 126 ciliochoroidal melanomas, three coincidental nevi that occurred in eyes with melanomas, and one magnocellular nevus collected from the Collaborative Ocular Melanoma Study to determine the effectiveness of the silver-stained nucleolar organizer region technique in assessing the malignant potential of these tumors. Malignant lesions demonstrated higher mean silver-stained nucleolar organizer region counts (4.347) than benign nevi (1.855) (P less than or equal to .0001). Among malignant melanomas, mixed-cell melanomas had slightly higher counts than spindle-cell melanomas (P less than or equal to .0001), but this difference was not important clinically. Results were also compared to other histopathologic variables, which disclosed correlation of silver-stained nucleolar organizer regions with mitoses and tumor size. Comparison with computerized cytomorphometric analyses of prognosis also disclosed significant correlation. This technique may prove to be a useful adjunct in the assessment of malignancy and treatment response of uveal melanomas.
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PMID:The value of nucleolar organizer regions in uveal melanoma. The Collaborative Ocular Melanoma Study Group. 170 Jun 11

Forty-one cases of typical melanocytic skin lesions (15 intradermal nevi, 14 Spitz nevi and 12 malignant melanomas) were used to investigate the value of staining of nucleolar organizer regions (NORs) in the differential diagnosis of such pigmented lesions. Histologic sections were stained by the silver colloid (Ag) method, with and without the prior use of a melanin blocking agent. There were statistically significant differences in the mean numbers of AgNORs per nucleus between the groups of lesions studied (1.658 for intradermal nevi, 3.0042 for Spitz nevi and 6.669 for malignant melanomas). Sections treated with potassium permanganate (melanin blocking agent) prior to staining showed an obvious increase in the AgNOR scores in all groups; this increase was highest for Spitz nevi. Although AgNOR staining allows a distinction to be made between intradermal nevi and malignant melanomas, the striking overlap between the counts for Spitz nevi and malignant melanomas precludes the use of this technique as the sole method for establishing the diagnosis of malignancy. Other clinical and morphologic data are especially required to make the diagnosis of Spitz nevi.
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PMID:Nucleolar organizer regions in pigmented skin lesions. Value in the differential diagnosis of Spitz nevi. 170 22

We applied a simple silver staining technique to visualize nucleolar organizer regions associated proteins (AgNORs) for the study of 47 melanocytic lesions (20 malignant melanomas, 5 dysplastic nevi, 4 Spitz nevi, 2 Reed and Gartman's fusiform nevi and 16 melanocytic nevi). A statistically significant difference existed between the numbers of AgNORs per cell in benign and malignant lesions as a group. However, some overlapping counts were found, limiting the usefulness of the technique in differentiating benign from malignant lesions in individual cases.
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PMID:Nucleolar organizer regions argyrophilic associated proteins in cutaneous melanocytic lesions. 174 75

Nucleolar organizer regions (NORs) are loops of ribosomal DNA seen in nuclei, which are demonstrable as black dots (AgNOR) in tissue sections by silver (Ag) colloid staining. The number of such AgNORs is correlated with cellular activity and is an indicator of the degree of malignancy. In this study, 76 melanocytic lesions were analyzed by AgNOR staining, and the clinical and histopathological characteristics of malignant melanoma and melanocytic nevi were considered. Although the AgNOR counts for melanocytic nevi were significantly different from those in malignant melanoma, an obvious overlap between them was detected. The number of AgNORs in melanocytic nevi per cell was usually 1 or 2. On the other hand, the number of AgNORs per malignant melanoma cell was variable. Morphologically, malignant melanoma cells often showed dispersal of AgNORs throughout the nucleus as well as multiple nucleoli containing clustered AgNORs, whereas melanocytic nevus cells tended to have a regular nucleolus with tightly clustered AgNORs. The correlation between AgNOR count and pathological staging was uncertain, but a slight correlation between AgNOR count and thickness of the primary lesion was obtained. However, the AgNOR count in malignant melanoma was not a prognostic factor for the disease. Therefore, the AgNOR method is difficult to use for differential diagnosis between benign pigmented lesions and malignant melanoma. Nonetheless, an AgNOR count of more than two per cell favors a diagnosis of malignant melanoma.
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PMID:AgNOR (nucleolar organizer regions) staining in malignant melanoma. 180 4

A silver colloidal technique to demonstrate argyrophilic proteins of the nucleolar organizer regions (AgNORs) was performed on sections of 20 cases of malignant melanoma (MM) associated with underlying benign nevus (BN). In these cases, significant different AgNOR counts were found for MM and BN. In addition, this technique permitted the identification of melanocytic cells located between malignant and benign cells showing AgNOR scores intermediate (5.51) between BN (2.6) and MM (7.71) with a more complex and bizarre morphology than that observed in BN. The AgNOR technique can be suitable in the identification of residual nevus cells in MM, especially when their number is minimal and the common histologic criteria are unsatisfactory; it can also increase the understanding of the natural history of MM.
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PMID:Argyrophilic nucleolar organizer region counts in malignant melanoma associated with benign intradermal nevus. 180 85


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